Method for using acoustic shock waves in the treatment of a diabetic foot ulcer or a pressure sore

ABSTRACT

A method of treating pathological conditions associated with bone and musculoskeletal environments and soft tissues involves applying acoustic shock waves to cause localized trauma, including micro-disruptions, non-osseous tissue stimulation, increased vascularization, and circulation and induction of growth factors to induce or accelerate the body&#39;s natural healing processes and responses.

This application is a continuation-in-part application of U.S.application Ser. No. 09/427,686, filed Dec. 23, 1998, now abandoned,which is a divisional of U.S. application Ser. No. 08/799,585, filedFeb. 12, 1997, now abandoned, which claims priority to U.S. ProvisionalApplication No. 60/014,742, filed Mar. 29, 1996, now abandoned, theentire contents of each of which are hereby incorporated by reference.

FIELD OF THE INVENTION

This invention relates to a method for medical treatment of pathologicalconditions. More particularly, the invention relates to a method forusing acoustic shock waves to treat a variety of pathological conditionsassociated with bone and musculoskeletal environments (including bone,cartilage, ligaments, tendons, fascia, joint capsules, bone marrow andmuscle) such as cutaneous, subcutaneous, and fascial geographic tissueinjuries, defects, or deficits; degenerative joint diseases; soft tissueinjuries; decalcification; osteochondromatosis and enchondromatosis;facet osteoarthritis; abnormal neuromuscular pain; and abnormalities ofdevelopment.

BACKGROUND OF THE INVENTION

Inventors have recognized the effectiveness of the use of energy waveforms for medical treatment of various pathologies. Extracorporeal shockwave therapy (ESWT) is the non-surgical treatment of medical conditionsusing acoustic shock waves. Lithotripsy, the use of shock waves tofragment kidney stones, was introduced in Europe in the early 1980s, andby the mid-1980s shock wave lithotripsy had been established worldwideas the treatment of choice for disintegrating kidney stones. In 1986,European researchers conducted animal experiments which revealed thatshock waves have the potential to stimulate bone formation by activationof osteoblast cells. The first positive results were reported afterapplication of shock waves to artificial humerus fractures in rats.Since then, further experimentation with shock waves for other medicaluses has continued, and today shock wave therapy has become an acceptedmethod of treatment for a number of orthopedic indications. This methodof treatment is increasingly popular with patients and physicians alikebecause it provides a non-surgical, non-invasive alternative forpatients.

A shock wave is a type of acoustic energy resulting from phenomena, suchas an explosion or lightning, that create a sudden intense change inpressure. The intense changes in pressure produce strong waves of energythat can travel through any elastic medium such as air, water, humansoft tissue, or certain solid substances such as bone. Early approachesof using shock waves for medical treatment required immersing thepatient in water and directing a shock wave, generated by an underwaterspark discharge, at a solid site to be treated, such as a bone or kidneystone. When the shock wave hits the solid site, a liberation of energyfrom the change of acoustic impedance from water to the solid siteproduces pressure in the immediate vicinity of the site.

Three methods are currently used to create the acoustic shock waves forESWT: (1) electrohydraulic, or spark gap; (2) electromagnetic, or EMSE;and (3) piezoelectric. Each is based upon its own unique physicalprinciples. Spark gap systems incorporate an electrode (spark plug) toinitiate a shock wave and ellipsoid to focus it. EMSE systems utilize anelectromagnetic coil and an opposing metal membrane. Piezoelectricsystems form acoustical waves by mounting piezoelectric crystals to aspherical surface.

In general, spark gap systems deliver the same level of energy as othermethods produce, but over a broader area, and therefore deliver agreater amount of positive shock wave energy to targeted tissue. Inspark gap systems, high energy shock waves are generated whenelectricity is applied to an electrode positioned in an ellipsoidimmersed in treated water. When the electrical charge is fired, a smallamount of water is vaporized at the tip of the electrode and a shockwave is produced. The shock wave ricochets from the side of an ellipsoidand converges at a focal point, which is the location of the area to betreated. Treatment areas are typically localized either by palpation orthrough the use of a fluoroscopy device.

The use of energy wave forms for medical treatment of various bonepathologies is known in the art. Some prior systems use ultrasoundtransducers, in direct contact with the skin of the patient, fortransmitting ultrasound pulses to the site of the bone defect. Otherdevices utilize piezoelectric materials fastened adjacent to thepathological site on the patient's limb to produce ultrasonic energy inthe vicinity of the bone pathology for administering therapy.

U.S. Pat. No. 4,905,671 to Senge et al. (“Senge”), issued on Mar. 6,1990, teaches a method of applying acoustic shock waves to induce boneformation. Senge teaches that the acoustical sound waves previously usedfor treatment of bone have a generally damped sinusoidal wave formcentered on ambient pressure. Senge differentiates an idealized shockwave from such acoustical sound waves in that the shock wave has asingle pressure spike with a very steep onset, a more gradualrelaxation, and virtually no oscillation to produce acoustic tension.

Senge utilizes the extremely short rise time of the shock wave to createhigh compression zones within bone tissue to cause restrictions of themicrocompartments of the bone. Senge purports that such restrictionscause the formation of hematomas within bone, which in turn, induce theformation of new bone. Senge utilizes a shock wave source consisting ofa spark gap between electrodes within a container of water. A metallic,ellipsoid-shaped structure surrounds a rear portion of the spark gap,opposite the patient, to produce a known focal point for positioningwithin the patient's pathological bone site. This device also requiresthat the patient be submerged in the water.

U.S. Pat. No. 4,979,501 to Valchanov et al. (“Valchanov”), issued onDec. 25, 1990, teaches a method and apparatus for treating bonepathologies with shock or “impact” waves for correction of delayed boneconsolidation and bone deformations. The method disclosed in Valchanovincludes treating the affected bone site once or consecutively for aperiod of 10–120 minutes and subsequently immobilizing the limb for aperiod from 15 to 90 days. The impact wave generating device disclosedby Valchanov generally consists of a vessel which contains atransmitting medium or acoustic liquid such as water contained therein.At a bottom portion of the vessel are opposed electrodes which areadapted to produce a shock across the gap. Therefore, the patient is notsubmerged for treatment.

Other references, including U.S. Pat. Nos. 5,284,143, 5,327,890,5,393,296, 5,409,446, and 5,419,327, teach the treatment of bonepathologies utilizing shock wave therapy in combination with imagingmeans for localizing the pathology during treatment. Still other devicesutilize transducers for producing ultrasonic waves for therapy of softtissue. These past methods for treating soft tissue surrounding boneutilized a transducer for the generation of ultrasonic waves for wavepropagation into the pathological site within the soft tissue area.Furthermore, as described by Senge, clinicians traditionally implementedshock wave therapy for the treatment of bone.

Therefore, what is needed is a rapid, time-restricted and effectiveshock wave therapy treatment for pathological conditions not onlyassociated with bones, but also bone and musculoskeletal environmentsand soft tissue.

SUMMARY OF THE INVENTION

The present invention relates to methods for treating pathologicalconditions associated with bones and musculoskeletal environments, aswell as soft tissue. More specifically, certain exemplary embodiments ofthe present invention include applying acoustic shock waves to the siteof a pathological condition associated with bone, a musculoskeletalenvironment, or soft tissue to induce, reactivate, or accelerate thebody's natural healing processes. Certain exemplary embodiments mayinclude the steps of locating the site of a pathological condition,generating acoustic shock waves, focusing the acoustic shock waves onthe pathological site, and applying the focused acoustic shock waves tothe site to induce localized trauma or micro-injury and increasedvascularization.

According to an embodiment of the present invention, acoustic shockwaves are used to treat a variety of pathological conditions associatedwith bone and musculoskeletal environments and soft tissue, such ascutaneous, subcutaneous, and fascial geographic tissue injuries,defects, or deficits and degenerative joint diseases, includingosteoporosis, osteomalacia, and arthritis. For the purposes of thisspecification, the musculoskeletal environment may include thecartilage, tendons, ligaments, joint capsules, fascia, and muscles whichfunctionally support skeletal structures.

In further embodiments of the present invention, exemplary methods maypromote fusion in partially ankylosed joints and reabsorption ofheterotopic calcifications and ossifications. Soft tissue injuries maybe treated, including damaged rotator cuffs, impingement syndrome, andtendonopathies. Additional pathologies that respond positively tocertain exemplary embodiments of the present invention includesacroiliac pain, osteochondromatosis and enchondromatosis, facetosteoarthritis, focal reflex dystrophy pain, phantom pain, andnon-adaptive bone disease and fatigue failure in equines and canines.

Some methods according to the present invention may also affect bonegrowth. Specifically, application of acoustic shock waves may induceearly closure of the growth plate (epiphyseodesis) and osteogenesis atmargins of vascularized bone transplants or transport bone in bonelengthening. Certain exemplary embodiments of the invention may alsopromote stimulation of bone formation and vascular ingrowth in bonelengthening and vascularized bone grafting.

Physical palpation, X-ray image intensification, or ultrasonography maybe used to precisely locate the pathological site. Once the site islocated, certain embodiments may utilize a spark gap generator togenerate acoustic shock waves and an ellipsoid reflector or focusinglens to specifically direct the acoustic shock waves to the impact(treatment) site. Other objects and features of the present inventionwill be more readily understood from the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of a shock wave generation devicewith a focusing mechanism used in accordance with the inventive method.

FIG. 2 is a schematic representation of a therapy head and locatingmechanism used in accordance with the inventive method.

FIG. 3 is a schematic representation of the therapy head and locatingmechanism of FIG. 2 with the locating mechanism situated at a 45 degreeangle with respect to a horizontal plane.

FIGS. 4 and 5 illustrate schematic representations of monitors thatdisplay images of alignment targets for the therapy head in unalignedand aligned positions, respectively.

DETAILED DESCRIPTION OF THE INVENTION

Certain exemplary embodiments of the present invention require the useof a locating device or palpation to locate the site or suspected siteof the pathological condition. Locating devices may include, but are notlimited to X-ray or ultrasound machines. For example, the method andapparatus described in U.S. Pat. No. 4,896,673 to Rose et al., issuedJan. 30, 1990, the disclosure of which is incorporated herein byreference in its entirety, may locate the site or suspected site of thepathological condition.

Certain exemplary embodiments of methods according to the inventionrequire a shock wave source such as a spark gap generator, such as theones described in U.S. Pat. No. 4,905,671 to Senge et al.; U.S. Pat. No.4,979,501 to Valchanov et al.; U.S. Pat. No. 5,284,143 to Rattner; U.S.Pat. No. 5,327,890 to Matura et al.; U.S. Pat. No. 5,393,296 to Rattner;U.S. Pat. No. 5,409,446 to Rattner; and U.S. Pat. No. 5,419,327 toRohwedder et al., the disclosures of each of which are herebyincorporated by reference in their entirety. Other exemplary embodimentsmay utilize the electromagnetic shock wave source and parabolic wavefocusing means of the type described in U.S. Pat. No. 5,327,890 toMatura et al., the disclosure of which is incorporated herein byreference in its entirety. The focusing means may also compriseparabolic reflectors such as those commonly utilized in kidneylithotripters.

Certain exemplary embodiments of the invention also require means forfocusing the acoustic shock waves with an appropriate device, such as anellipsoid reflector or parabolic focusing lens. The reflector isgenerally located in a therapy head, which directs the waves to a focalpoint. FIG. 1 is a schematic representation of such a shock wavegenerator and focusing means. Shock waves 4 radiate from an electrode 9and through water (not shown). Waves 4 reflect from an ellipsoid surface8 and toward a focal point 10.

In an exemplary embodiment, the therapy head also includes a targetingdevice which functions in conjunction with an X-ray machine locatingdevice, as is illustrated in FIGS. 2 and 3. FIGS. 2 and 3 schematicallyillustrate a patient 56 positioned on a surface 55 during a treatmentsession. Two movable targets 25 and 26 are connected mechanically to atherapy head 20 so that the pair of targets 25 and 26 may rotate aroundat least two different axes with an imaginary connecting line 19. AnX-ray source 21 and a plate 22 define a connecting line 19 which passesthrough targets 25 and 26. Connecting line 19 always extends between thetwo targets and through focal point 10 of the shock waves.

Before beginning treatment in accordance with certain exemplaryembodiments of the present invention, the clinician aligns the tissuearea to be treated with the approximate center of an X-ray image beingprojected by source 21. An appropriate monitor 29 illustrates theprojection of the X-ray image as illustrated in FIGS. 4 and 5. Asillustrated in FIG. 4, when targets 25 and 26 do not coincide with oneanother, then focal point 10 is not aligned with the treatment site.After proper alignment, as shown in FIG. 5, targets 25 and 26 coincidewith the treatment site, and the clinician may begin treatment. Asillustrated in FIG. 3, the imaging mechanism may also be positioned atvarious angles with respect to the patient depending on the location ofthe treatment site within the patient. Alternatively, an ultrasoundlocating unit positions the shock wave focal point between the patient'spathological site and the acoustically reflective object.

Certain exemplary embodiments of the present invention include methodsof applying acoustic shock waves to the site of a pathological conditionassociated with bone, a musculoskeletal environment, or soft tissue toinduce, reactivate, or accelerate the body's natural healing processes,especially through natural cellular and molecular (macromolecular)biologic responses, including the stimulation of tissue specific groupfactors (cytokines, morphogenic proteins), and to improve localmicrocirculation through activated neoangiogenesis.

Certain exemplary embodiments of the present invention may furtherinclude locating the site or suspected site of a pathological condition,generating acoustic shock waves, focusing the acoustic shock waves onthe located site, and applying the focused acoustic shock waves to thesite to induce localized trauma and cellular apotosis therein, includingmicro-fractures, as well as to induce osteoblastic responses such ascellular recruitment, stimulate formation of molecular bone, cartilage,tendon, fascia, and soft tissue morphogens and growth factors, and toinduce vascular neoangiogenesis. Application of acoustic shock wavessimilarly induces neoangiogenesis in musculoskeletal environment tissuesand the formation, recruitment, or stimulation of tissue specificmorphogenetic macromolecules and growth factors.

Micro-disruptions resulting from the shock wave therapy inducedisruption of small blood vessels (capillaries), cellular changes, andextracellular matrix and macromolecular changes in a controlled fashionfor the purpose of stimulating increased neoangiogenesis leading toadequate revascularization in ischemic tissues. The increasedcirculation and revascularization then induce the body's naturalcellular (tissue specific) healing processes. The accompanying cellularchanges lead to or are associated with elaboration and production ofbone and tissue morphogenetic proteins, known as growth factors, as wellas elaboration and production of nitric oxide synthase isoforms.

Applicants have found unexpected success in the treatment of soft tissueand cancellous bone pathologies using acoustic shock wave therapy.Particular applications of shock wave therapy are illustrated in thefollowing example studies, which include patients that did notsignificantly respond to conventional treatments for the particularpathology treated.

EXAMPLE 1

Acoustic shock waves were used to treat calcified tendinitis, whereinthe affected tendon is inflamed and has developed deposits of calciumsalts. A tendon, which is the fibrous corridor band that connects amuscle to a bone or other structure, consists of very densely arranged,almost parallel collagenous fibers, rows of elongated tendon cells, anda ground substance. The tendon may become calcified, stiff, andinflamed. Table 1 below sets out results of acoustic shock wave therapyfor the treatment of calcific tendinitis:

TABLE 1 Preliminary Clinical Results For Treatment of CalcificTendinitis using Acoustic Shock Waves Number of patients: 684 SuccessRate: total 81% single treatment: 62% double treatment: 19% Shocks PerTreatment: average: 750 min: 300 max: 2500 Energy Applied average: 16 kVPer Pulse: min: 14 kV max: 18 kV Pulse Frequency: average: 0.5–4.0 HzTreatment Duration average: 20–30 minutes Anesthesia: local SideEffects: petechial bleedings History: Time of prior conventionaltherapies: average: 15 months min: 6 months max: 12 years Priortreatment: Resistant to conventional methods Hospitalization: OutpatientFollow-up: 3–6 months

The treatment included 684 patients with calcific tendinitis with anaverage success rate of 81%. Of the total number of treated patients,62% of the patients had a successful recovery after one session, and 19%had a successful recovery after two sessions of acoustic shock wavetherapy. An average of 750 shocks per treatment were applied with theminimum being 300 and the maximum being 2500.

The average amount of energy applied for each shock wave pulse was 16kilovolts with a session minimum of 14 kilovolts and a session maximumof 18 kilovolts. The treatment included local anesthesia, and the sideeffects of the treatment included petechial bleedings, which are minutehemorrhagic spots approximately the size of pin points on the patient'sskin surface, in the vicinity of the treatment site. These resolvewithin 48 hours with no permanent consequences.

As explained above, each of the patients chosen for this study had notresponded to previous conventional therapy. Of the total number ofpatients treated using acoustic shock wave therapy for calcifictendinitis, the average time for conventional treatment period was 15months with no response. The maximum prior conventional prior treatmentperiod was 12 years. The minimum prior treatment period for the group ofpatients was 6 months. Each patient received the shock wave therapy onan outpatient basis, and follow up examinations after 3–6 months foreach patient yielded no recurrence of the condition.

EXAMPLE 2

Acoustic shock wave therapy also proves successful in the treatment ofepicondylitis. Epicondylitis refers to a condition which may necessitatethe removal of an inflamed or diseased external condyle from anelongated bone or the release or repair of attached tendons and fascia.The epicondyle is generally a projection from an elongated bone near itsarticular extremity. Table 2 summarizes the results of acoustic shockwave treatment on patients suffering from epicondylitis at the elbow.

TABLE 2 Preliminary Clinical Results For Treatment of EpicondylitisUsing Acoustic Shock Waves Number of patients: 285 Success Rate: total69% single treatment: 47% double treatment: 22% Shocks Per Treatment:average: 780 min: 400 max: 1500 Energy Applied Per Pulse: average: 15 kVmin: 14 kV max: 16 kV Pulse Frequency: average: 0.5–4.0 Hz TreatmentDuration average: 20–30 minutes Anesthesia: local plexus Side Effects:petechial bleedings, post-treatment pain History: Time of priorconventional therapies: average: 13 months min: 4 months max: 48 monthsPrior treatment: Resistant to conventional methods Hospitalization:Outpatient Follow-up: 3–6 months

This study included 285 patients treated with an average success rate of69%. The average success rate consisted of a sum of 47% of the treatedpatients receiving a single treatment and 22% of the treated patientsreceiving a double treatment. Each treatment employed an average numberof shocks applied per session of 780, with the minimum being 400 and themaximum being 1500. The treatment applied an average of 15 kilovoltsenergy per pulse with the minimum being 14 kilovolts and the maximum 16kilovolts. Treatment included a local or plexus anesthesia. The sideeffects included petechial bleedings and post-treatment pain, both ofwhich subsided rapidly.

As explained above, each of the patients chosen for this study did notrespond to conventional therapy. Of the total number of patients treatedusing acoustic shock wave therapy for epicondylitis, the average timefor conventional treatment period was 13 months with no response. Themaximum prior conventional prior treatment period was 48 months. Theminimum prior treatment period for the group of patients was 4 months.Each patient received the acoustic shock wave therapy on an outpatientbasis, and follow up examinations after 3–6 months for each patientyielded no reoccurrence of the condition.

EXAMPLE 3

This study included treatment for 131 patients suffering frompseudarthrosis, which is a condition wherein a new, false joint arisesat the site of a non-united fracture, as illustrated in Table 3.

TABLE 3 Preliminary Clinical Results For Treatment of PseudarthrosisUsing Acoustic Shock Waves Number of patients: 131 Success Rate: total77% single treatment: 57% double treatment: 20% Shocks Per Treatment:average: 2450 min: 800 max: 4000 Energy Per Pulse: average: 24 kV min:18 kV max: 28 kV Pulse Frequency: average: 0.5–4.0 Hz Treatment Durationaverage: 30–40 minutes Anesthesia: general, spinal, peridural, localSide Effects: petechial bleedings, local swelling History: Time of priorconventional therapies: average: 23 months min: 4 months max: 20 yearsPrior treatment: One or multiple surgeries, including osteosynthesisHospitalization: usually outpatient Follow-up: 3–6 months

This study included 131 patients treated with an average success rate of77%. The average success rate consisted of a sum of 57% of the treatedpatients receiving a single treatment and 20% of the treated patientsreceiving a double treatment. The treatment employed an average numberof shocks applied per session of 2450, with the minimum being 800 andthe maximum being 4000. The treatment applied an average of 24 kilovoltsenergy per pulse with the minimum being 18 kilovolts and the maximum 28kilovolts. Treatment included one or more of the following types ofanesthesia: general, spinal, peridural, and local. The side effectsincluded petechial bleedings and local swelling, both of whichdissipated rapidly.

As explained above, each of the patients chosen for this study did notrespond to conventional treatment for fracture and faced furthersurgery, bone grafting, etc. Of the total number of patients treatedusing acoustic shock wave therapy for pseudarthrosis, the average timeafter fracture was 13 months. The maximum time period from fracture was20 years. The minimum time period from fracture was 4 months. Priortreatment for this group of patients included one or multiple surgeriesincluding osteosynthetic procedures. Each patient received the acousticshock wave therapy on an outpatient basis or over a 2–3 day hospitalvisit, and follow up examinations after 3–6 months for each patientyielded no recurrence of the condition.

Table 4 below summarizes the technical parameters of methods for usingacoustic shock waves in the treatment of some medical conditions.

TABLE 4 Summary of Technical Parameters of Various Acoustic Shock WaveTreatment Parameters Calcific Tendinitis Epicondylitis PseudarthrosisPlantar Fasciitis Frequency of 0.5–4.0 Hz @ 0.5–4.0 Hz @ 0.5–4.0 Hz @0.5–4.0 Hz @ shock wave fixed frequency fixed frequency fixed frequencyfixed frequency impact Pulse average rise average rise average rise timeaverage rise time duration time 33 ns; time 33 ns; 33 ns; average 33 ns;average average pulse average pulse pulse width 280 pulse width 280width 280 ns width 280 ns ns ns Treatment as needed to as needed to asneeded to as needed to period identify identify identify treatmentidentify treatment (minutes) treatment site treatment site site(s) anddeliver site and deliver up and deliver up and deliver up from 1000 toto 1000 pulses, to 2500 pulses, to 1500 pulses, 8000 pulses, approx.20–30 approx. 20–30 approx. 20–30 approx. 45–60 min min min minPosttreatment return to normal return to normal recast and treat returnto normal care activities activities as fresh fracture activities Tissuetype at tendons of tendons of the fractured bone fascia of the heelfocal point shoulder joint at elbow joint at that has delayed at theinsertion the insertion the intersection or failed to heal into boneinto bone into bone Types of application of application of dynamicinternal application of ineffective heat, ice heat, ice or externalheat, ice conventional physical physical fixation physical therapytherapy therapy therapy immobilization Non-steroidal Non-steroidalNon-steroidal surgical anti- anti- anti- debridement inflammatoryinflammatory inflammatory electrical/ drugs (NSAIDs) drugs drugselectromagnetic Steroid injection (NSAIDs) (NSAIDs) bone growth SurgicalSteroid Steroid stimulator Intervention injection injection SurgicalSurgical Intervention Intervention

While the examples and tables above focus on the treatment of fourselected pathological conditions, acoustic shock wave therapy is furtherapplicable to a wide range of pathological conditions. Certain exemplaryembodiments of the invention may include a wide range in the variousparameters used to treat all of the pathologies mentioned in thisspecification. Specifically, for each of the pathologies mentioned inthis specification, an exemplary embodiment of the invention may includeapplying a range of approximately 14–28 kilovolts of energy per pulse;the pulse frequency may be approximately 0.5–4 Hz (pulses/sec), and thepulse duration may be approximately 280 ns. The number of pulses pertreatment should be approximately 500–8,000, and the total time pertreatment should be approximately 20 minutes to 3 hours. The totalenergy per treatment may be from 2500 to 150,000 mJ. Additionally, thenumber of treatments necessary for a positive response may vary from 1to 3 for each pathology discussed below. For all of the pathologicalconditions below, there is typically an increasing benefit foradditional treatments, with most indications requiring an average of 1.5treatments.

Although the several methods of shock wave generation and variousphysical parameters have been discussed above, a brief discussion ofvarious energy parameters used by those skilled in the art may also behelpful. For more detailed information than that provided below, thereader is referred to the publication entitled “Principles of Shock WaveTherapy” by John A. Ogden, M. D. et al. in Clinical Orthopaedics andRelated Research, No. 387, pp. 8–17, said publication being incorporatedherein by reference in its entirety.

Energy flux density is a measure of the energy per square area that isbeing released by the sonic pulse at a specific, finite point. Energyflux density may be derived from pressure and can be computed as thearea below the squared pressure time curve. The pressure (typicallymeasured in MPa) generated by a shock wave as a function of time andspace is the parameter that is most amenable to direct measurement. Thepressure field is maximal at the focal center, but in addition,significant effects may be produced over neighboring regions of tissueand the dimensions of such zones will vary according to the preciseshock wave treatment provided. The zone around the focal region may bedefined in three different axes to create the focal volume.

Energy flux density should not be confused with energy. The energy flux(as much as 1.5 mJ/mm²) and the peak pulse energy (as many as 100 MPa)are determined by the temporal and spatial distribution of the pressureprofile. The energy flux density describes the maximum amount ofacoustical energy that is transmitted through an area of 1 mm² perpulse. The total pulse energy is the sum of all energy densities acrossthe beam profile and describes the total acoustical energy per releasedshock wave. Although energy flux density relates to the energy releasedat a certain point, the energy of a shock wave is the total amount ofenergy released within a defined region.

The total energy applied to the tissue is represented by the number ofpulses multiplied by the energy per pulse. Theoretically, pressure andenergy are concentrated within a point, the focus. The treatment focushas finite dimensions. The pressure is highest in the focal center anddecreases with increasing distance from the focus. According toultrasound physics, the focal regions of a shock wave may be defined bythree different conditions: the 5 mm area, the 6 dB area, and the 5 MPaarea. The 5 mm area is simply a sphere surrounding the treatment focalpoint whose radius is 5 mm. The 6 dB area may be defined as the volumeof tissue in millimeters within which the pressure is at least half itspeak value. The 5 MPa area may be defined in a similar fashion as thevolume of tissue defined in millimeters along x, y, and z axes withinwhich the pressure exceeds 5 MPa.

The volume within these defined boundaries should be assessed for themaximum, minimum, and intermediate energy settings of any relevant shockwave device. The physical parameters of positive peak pressure and thevarious zones in the clinically sensitive −6 dB focal areas for high-,medium-, and low-energy devices is available from the InternationalSociety for Musculoskeletal Shock Wave Therapy (www.ismst.com).Measurements have been completed using unified standards, and theindividual values of the various devices on the market (especially inEurope) or being tested (in the United States) are published by theGerman and International Society for Extracorporeal Shock Wave Therapy(www.shockwavetherapy.net). An exemplary shock wave device is theOssatron®, which is manufactured by HMT High Technologies AG of Lengwil,Switzerland. The physical parameters of the Ossatron® are reproduced inTable 5 below:

TABLE 5 Focal Focal Energy extend extend flux in x, y in z Volt- densityEnergy- Energy- Energy- direc- direc- age Pressure (mJ/ 6 dB 5 mm 5 MPation tion (kV) (MPa) mm²) (mJ) (mJ) (mJ) (−6 dB) (−6 dB) 14 40.6 0.124.9 2.9 22.2 6.8 44.1 15 40.9 0.14 4.9 3.3 22.5 6.7 48 16 41.3 0.17 4.93.9 23.4 6.7 51 17 42 0.19 5 4.4 24.9 6.7 53.5 18 42.9 0.22 5 4.9 27.26.7 55.6 19 44.1 0.25 5 5.5 30.2 6.7 57.4 20 45.6 0.27 5.1 5.8 34.2 6.459 21 47.4 0.29 6.2 6.5 39.2 6.8 60.4 22 49.6 0.32 7.7 7.1 45.3 6.9 61.723 52.2 0.34 9.7 7.6 52.6 7.1 62.9 24 55.2 0.36 12.2 8.2 61.1 7.3 64 2558.7 0.37 15.2 8.7 71.1 7.6 65 26 62.6 0.38 18.8 9.2 82.5 7.9 65.9 27 670.39 23.1 9.8 95.5 8.3 66.8 28 71.9 0.4 28 10.4 110.2 8.7 67.9It should be understood that embodiments of this invention are notlimited to embodiments utilizing the Ossatron® or the other systems anddevices described above for generating, focusing, and/or applyingacoustic shock waves.

A certain threshold value of energy density has to be exceeded tostimulate any healing process, and to lead to any significant sideeffects. Such a threshold dosage of energy is not different fromconcepts such as bacteriocidal and bacteriostatic effects of anantibiotic. Although the energy density (mm²/mJ) of a shock wave isimportant, the more clinically relevant physical parameter may be thetotal amount of acoustic energy administered in a single shock wavetreatment.

An embodiment according to the present invention may accelerate thehealing of pathologic cutaneous, subcutaneous, and fascial geographictissue injuries, defects, and deficits, such as diabetic foot ulcers orpressure sores. Application of acoustic shock waves disrupts the thicknecrotic tissue, causing breakdown, which then enhancesrevascularization of the pathologic tissues, creating a granulomatousbase that allows for progressive migration and maturation of dermal andepidermal tissues. Furthermore, the acoustic shock waves may disrupt thecapsules of infecting bacteria, enhancing the uptake of antibiotics.Such an acoustic shock wave treatment should apply an average ofapproximately 14–26 kilovolts, more preferably 20–26 kV, of energy perpulse. The pulse frequency should be approximately 0.5–4.0 Hz and thepulse duration should be approximately 280 ns. The number of pulses pertreatment may be more than 500 to about 2500, and a range of more than1000 to about 2500 is more preferable. The total time per treatmentshould be in the range of approximately 20 to 60 minutes, and the totalenergy per treatment should be about 2500 to about 12,500 mJ.

An embodiment according to the present invention may also be used totreat arthritis and other degenerative joint diseases, includingrheumatoid arthritis, osteoporosis, and osteomalacia. The treatment forthose conditions should include an average number of shocks applied persession of about 500 to about 2500. The treatment should apply anaverage of approximately 14–28 kilovolts of energy per pulse. The pulsefrequency should be approximately 0.5–4.0 Hz, and the pulse durationshould be approximately 280 ns. The total time per treatment should bein the range of approximately 20 to 45 minutes, and the total energy pertreatment should be about 5000 to about 15,000 mJ.

Acoustic shock waves may also be used to accelerate the rate of healingof soft tissue injuries, such as damaged rotator cuffs. Such a treatmentshould apply an average of approximately 14–28 kilovolts of energy perpulse. The pulse frequency should be approximately 0.5–4.0 Hz, and thepulse duration should be approximately 280 ns. The number of pulses pertreatment should be about 500 to about 2500, and the total time pertreatment should be in the range of approximately 20 to 45 minutes. Thetotal energy per treatment should be about 2500 to about 15,000 mJ.

The reabsorption of impending heterotopic calcifications andossifications may also be accelerated by application of an exemplaryembodiment of a method according to the present invention. Focusingacoustic shock waves on the site associated with the impendingheterotopic calcification or ossification fragments the impendingheterotopic calcification or ossification microscopically, therebyaccelerating healing. In particular, the surrounding shell and fibroticcapsule protecting the calcification or ossification from thereabsorption process would be destroyed or damaged. Such a treatmentshould apply an average of approximately 14–28 kilovolts of energy perpulse. The pulse frequency should be approximately 0.5–4.0 Hz, and thepulse duration should be approximately 280 ns. The number of pulses pertreatment should be about 1000 to about 4000, and the total time pertreatment should be in the range of 20 minutes to 1 hour. The totalenergy per treatment should be about 28,000 to about 115,000 mJ.

An exemplary embodiment of the invention may be used to treat sacroiliacpain, wherein the acoustic shock waves are focused between the sacrumand pelvic bone surface (ilium). Such a treatment should apply anaverage of approximately 14–28 kilovolts of energy per pulse. The pulsefrequency should be approximately 0.5–4.0 Hz, and the pulse durationshould be approximately 280 ns. The number of pulses per treatmentshould be about 1500 to about 4000, and the total time per treatmentshould be in the range of approximately 40 to 90 minutes. The totalenergy per treatment should be about 32,000 to about 115,000 mJ.

An exemplary embodiment of the invention may be used to treatosteochondromatosis and enchondromatosis (tumors of the growth plate),as well as facet osteoarthritis. Applying a sufficient number ofacoustic shock waves induces micro-injury and increased vascularizationin order to slow or stop abnormal activity of the genetically alteredgrowth cartilage associated with osteochondromatosis orenchondromatosis. Treatment generally involves applying an average ofapproximately 14–28 kilovolts of energy per pulse. The pulse frequencyshould be approximately 0.5–4.0 Hz, and the pulse duration should beapproximately 280 ns. The number of pulses per treatment should be about1000 to about 5000, and the total time per treatment should be in therange of approximately 20 to 150 minutes. The total energy per treatmentshould be about 28,000 mJ to about 140,000 mJ.

Examples of additional pathological conditions which respond positivelyto certain exemplary embodiments of the present invention include focalreflex dystrophy pain, phantom pain, and focal pain due to an abnormalenlargement of a nerve (such as a neuroma). Treatments for thesepathological conditions generally involve applying an average ofapproximately 14–28 kilovolts of energy per pulse. The pulse frequencyshould be approximately 0.5–4.0 Hz, and the pulse duration should beapproximately 280 ns. The number of pulses per treatment should be about1000 to about 5000, and the total time per treatment should be in therange of approximately 20 to 150 minutes. The total energy per treatmentshould be about 3000 to about 10,000 mJ.

Other exemplary embodiments of the invention may promote stimulation ofbone formation and vascular ingrowth in bone lengthening, fusion inpartially ankylosed joints, and selective partial or complete closure ofgrowth cartilage in cases of bone length inequality or angulardeformity. Treatments for these pathologies should apply an average ofapproximately 14–28 kilovolts of energy per pulse. The pulse frequencyshould be approximately 0.5–4.0 Hz, and the pulse duration should beapproximately 280 ns. The number of pulses per treatment should be about1000 to about 5000, and the total time per treatment should be in therange of approximately 20 to 150 minutes. The total energy per treatmentshould be about 28,000 to about 140,000 mJ.

An exemplary embodiment according to the invention may be used to treatrepetitive motion injuries including carpal tunnel and tarsal tunnelsyndromes. Such a treatment should apply an average of approximately14–28 kilovolts of energy per pulse. The pulse frequency should beapproximately 0.5 to 4.0 Hz, and the pulse duration should beapproximately 280 ns. The number of pulses per treatment should beapproximately 500–2500, and the total time per treatment should be inthe range of approximately 20 minutes to 45 minutes. The total energyper treatment should be about 5000 to about 15,000 mJ.

The bone density and extent of calcification in osteoporotic sites canbe increased according to an embodiment of the present invention. Theeffects of the focused acoustic waves on osteoporotic sites can beprolonged and maintained indefinitely when used in conjunction withdrugs such as Fosamax™. For example, an osteoporotic wrist requires atreatment having an average of approximately 14–28 kilovolts of energyper pulse. The pulse frequency should be approximately 0.5 to 4.0 Hz andthe pulse duration should be approximately 280 ns. The number of pulsesper treatment should be approximately 800–4000, the total time pertreatment should be in the range of approximately 30 minutes to 1 hourand 30 minutes, and the total energy per treatment should be about28,000 to about 140,000 mJ. The inventive treatment is also effective onother osteoporotic sites. However, the number of pulses per treatmentmust increase with increasing bone mass. For example, an osteoporotichip may require up to 8,000 shocks in a single treatment.

Acoustic shock waves may be used to enhance bone formation andremodeling in stress fractures. Such a treatment should apply an averageof approximately 14–28 kilovolts of energy per pulse. The pulsefrequency should be approximately 0.5–4.0 Hz, and the pulse durationshould be approximately 280 ns. The number of pulses per treatmentshould be approximately 1000–8000, and the total time per treatmentshould be in the range of approximately 45 minutes to 2 hours. The totalenergy per treatment should be about 28,000 to about 140,000 mJ.

Non-adaptive bone diseases in equines and canines may also be treatedusing acoustic shock waves. For example, to the extent that all of theabove-referenced pathological conditions occur in equines and canines,all of the above-referenced treatments are applicable to the treatmentof equines, canines, or other animals.

The foregoing description of the exemplary embodiments of the inventionhas been presented only for the purposes of illustration and descriptionand is not intended to be exhaustive or to limit the invention to theprecise forms disclosed. Many modifications and variations are possiblein light of the above teaching.

The embodiments were chosen and described in order to explain theprinciples of the invention and their practical application so as toenable others skilled in the art to utilize the invention and variousembodiments and with various modifications as are suited to theparticular use contemplated. Alternative embodiments will becomeapparent to those skilled in the art to which the present inventionpertains without departing from its spirit and scope. Accordingly, thescope of the present invention is defined by the appended claims ratherthan the foregoing description and the exemplary embodiments describedtherein.

1. A method of treating a diabetic foot ulcer or a pressure sore,comprising: locating a site or suspected site of the diabetic foot ulceror pressure sore in a human patient; generating acoustic shock waves;focusing the acoustic shock waves throughout the located site; andapplying more than 500 to about 2500 acoustic shock waves per treatmentto the located site to induce micro-injury and increased vascularizationthereby inducing or accelerating healing.
 2. The method of claim 1,wherein more than 1000 acoustic shock waves are applied per treatment.3. The method of claim 1, wherein generating acoustic shock wavescomprises applying a voltage potential across a spark gap of a spark gapgenerator ranging from about 14 kV to about 26 kV to generate each shockwave.
 4. The method of claim 1, wherein applying acoustic shock wavescomprises applying the acoustic shock waves in a single treatment. 5.The method of claim 1, wherein a total energy applied to the locatedsite per treatment is about 2,500 to about 12,500 mJ.
 6. The method ofclaim 1, wherein more than 500 to about 1000 acoustic shock waves areapplied per treatment.
 7. The method of claim 1, wherein more than 1000to about 2500 acoustic shock waves are applied per treatment.
 8. Themethod of claim 1, wherein a total time per treatment is in a range ofapproximately 20 to 60 minutes.
 9. The method of claim 1, wherein theacoustic shock waves disrupt capsules of infecting bacteria at thelocated site.
 10. The method of claim 1, wherein the locating stepincludes locating a site or suspected site of the diabetic foot ulcer inthe human patient.
 11. The method of claim 1, wherein the locating stepincludes locating a site or suspected site of the pressure sore in thehuman patient.